WPO: Floodplain Protection 10/21/2011 1 Watershed Protection Ordinance (WPO): Stakeholder Meeting FLOODPLAIN PROTECTION Watershed Protection Ordinance (WPO): Stakeholder Meeting FLOODPLAIN PROTECTION October 21, 2011 October 21, 2011 Meeting Agenda 1. Introductions 2. Current regulations 3. What we are losing 4. Where we want to go 5. Small group discussion 6. Full group review Council Resolution 20110113-038: Floodplain Protection • Preserve & restore floodplains and stream buffers • Provide access and connectivity with greenways and trails • Explore better ways to regulate the modification of floodplains • Simplify development regulations, minimize development impacts NOT redefining floodplain or changing No Adverse Impact Focus on Natural & Traditional Character Natural & Traditional Character (NTC) • Defined in 1974 • Identifying NTC is based on existing conditions using ECM 1.7.0*: – Mature Woodlands – Wetlands – Permanent Natural Pools • If NTC was eliminated in the past, not considered as protected • Limiting development using NTC is rare – relegated to ECM glossary *ECM = Environmental Criteria Manual Natural & Traditional Character (NTC) 1. Land Development Code • § 25-7-61 [City Limits]: To the greatest extent feasible, the proposed development preserves the natural and traditional character of the land and the waterway • § 25-8-261: Except in the Barton Springs Zone, detention basins and floodplain alterations are permitted in the critical water quality zone if the requirements of Chapter 25-7 (Drainage) and the other provisions of this subchapter are met. • § 30-4-61 [ETJ]: More detailed than 25-7-61 Natural & Traditional Character (NTC) 2. Environmental Criteria Manual • 1.7.0 Floodplain Modification Criteria: Used in assuring that development activities maintain the "natural and traditional character" of the land and waterways • Glossary – Protected Riparian Areas: Those ecological features within a floodplain associated with a waterway segment, which contribute to the natural and traditional character of the waterway, as follows: 1. Floodplain woodlands – Standards for size, canopy cover, and species composition 2. Wetlands (other than springs) 3. Permanent natural pools in perennial or intermittent waterways
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WPO: Floodplain Protection 10/21/2011 - Austin, Texasaustintexas.gov/sites/default/files/files/Watershed/wpo_handout_10_21_11.pdfcharacter" of the land and waterways • Glossary –Protected
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WPO: Floodplain Protection 10/21/2011
1
Watershed Protection Ordinance (WPO):
Stakeholder Meeting
FLOODPLAIN PROTECTION
Watershed Protection Ordinance (WPO):
Stakeholder Meeting
FLOODPLAIN PROTECTION
October 21, 2011October 21, 2011
Meeting Agenda
1. Introductions
2. Current regulations
3. What we are losing
4. Where we want to go
5. Small group discussion
6. Full group review
Council Resolution 20110113-038: Floodplain Protection
• Preserve & restore floodplains and stream buffers
• Provide access and connectivity with greenways and trails
• Explore better ways to regulate the modification of floodplains
• Simplify development regulations, minimize development impacts
���� NOT redefining floodplain or changing No Adverse Impact
���� Focus on Natural & Traditional Character
Natural & Traditional Character (NTC)
• Defined in 1974
• Identifying NTC is based on existingconditions using ECM 1.7.0*:– Mature Woodlands
– Wetlands
– Permanent Natural Pools
• If NTC was eliminated in the past, not considered as protected
• Limiting development using NTC is rare –relegated to ECM glossary
*ECM = Environmental Criteria Manual
Natural & Traditional Character (NTC)
1. Land Development Code
• § 25-7-61 [City Limits]: To the greatest extent feasible, the proposed development preserves the natural and traditional character of the land and the waterway
• § 25-8-261: Except in the Barton Springs Zone, detention basins and floodplain alterations are permitted in the critical water quality zone if the requirements of Chapter 25-7 (Drainage) and the other provisions of this subchapter are met.
• § 30-4-61 [ETJ]: More detailed than 25-7-61
Natural & Traditional Character (NTC)
2. Environmental Criteria Manual• 1.7.0 Floodplain Modification Criteria: Used in assuring that
development activities maintain the "natural and traditional character" of the land and waterways
• Glossary – Protected Riparian Areas: Those ecological features within a floodplain associated with a waterway segment,which contribute to the natural and traditional character of thewaterway, as follows:
1. Floodplain woodlands
– Standards for size, canopy cover, and species composition
2. Wetlands (other than springs)
3. Permanent natural pools in perennial or intermittent waterways
WPO: Floodplain Protection 10/21/2011
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Manning’s n Roughness Coefficient
• Mathematical coefficient used by engineers in floodplain modeling
• Represents the degree of resistance to flood flows in channels and floodplains caused by vegetation and other obstacles
• Reflects the relationship between the typical height of vegetation and the depth of flow
Where We Are Now
• If Natural & Traditional Character (NTC) is identified, floodplain modification is restricted to retain integrity of riparian areas
– Minimizes damage to physical and biological characteristics of such areas
• If no Natural & Traditional Character is identified, then floodplain modification is allowed, even within the Critical Water Quality Zone (CWQZ) buffer
WPO: Floodplain Protection 10/21/2011
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What We Are Losing
• Natural resources and functions of floodplains
•Water Resources
•Biological Resources
•Societal Resources
• Natural resources and functions of floodplains
•Water Resources
•Biological Resources
•Societal Resources
Water Resources
Natural Flood & Erosion Control
• Provide flood storage and conveyance
• Reduce peak flows • Reduce flood velocities
• Reduce sedimentation
Water Quality Maintenance • Filter nutrients and impurities from runoff
• Process organic wastes • Moderate temperature fluctuations
• Groundwater Recharge
• Promote infiltration and aquifer recharge
Biological Resources
Biological Productivity
• Rich, alluvial soils promote vegetative growth
• Maintain biodiversity • Maintain integrity of ecosystems
Fish & Wildlife Habitats • Provide breeding and feeding grounds
• Create and enhance waterfowl habitat
• Protect habitats for rare and endangered species
Natural Floodplain Functions
Source = Unified National Program for Floodplain Management, 1994
Societal Resources
Harvest of Wild & Cultivated
Products
• Enhance agricultural lands
• Provide sites for aquaculture
• Restore & enhance forest lands
Recreational Opportunities
• Provide areas for active &
passive uses
• Provide open space
• Provide aesthetic pleasure
Areas for Scientific Study &
Outdoor Education
• Contain cultural resources (historic & archeological sites)
• Provide opportunities for environmental and other studies
Natural Floodplain Functions
Source = Unified National Program for Floodplain Management, 1994
FEMA’s Community Rating System
• CRS recognizes communities which go beyond minimum federal standards
• FEMA revising regulations to encourage comprehensive approach to floodplain management
• Revised criteria provide credit to communities that work to preserve green space, natural floodplain functions, and connectivity within their waterways
“When you alter a natural system, it requires greater and greater amounts of energy to sustain the alteration.
And at some point you have to change what you’re doing.”
Major General Don Riley (U.S. Army Retired Commander of the USACE
Vicksburg Division, Chair of the Mississippi River Commission), Texas Water Conservation Association Fall Technical Conference, October 2011